A Filling Machine for the Non Flammable Chemical Industry – Foam control – Economy – Safety

Agricultural chemicals, fertilizers, cleaning chemicals and general industrial chemicals comprise what we refer to as the Non-Flammable Chemical Industry (NFCI). These products all share several economic and product handling characteristics. They are usually low value/low margin products and are often sold in bulk sizes. Many of these products are also very foamy and some are also inherently hazardous to the personnel that are packaging them.

All the considerations above will dictate what type of filling machine is the most practical to use for a chemical product or a range of chemical products. Sometimes the choices of these machines are mutually exclusive to each other and that a compromise needs to be made.

In the case of chemicals that are highly foamy but not inherently dangerous to personnel, e.g. cleaning and sanitation chemicals, an Overflow Filling Machine may be the best choice. In the case of chemicals where the major consideration is safety to personnel, e.g. strong acids or toxicity, a time gravity filler may be the best choice. In the case where bulk filling in very large containers is the primary format, a net weigh filling machine may be the best choice. As mentioned above, products in this industry can be both foamy and hazardous and a value judgment must be made. Sometimes it is necessary to compromise performance in the interest of safety. These decisions can be tricky and are best made with the help our applications engineers with years of expert experience.

Chemical products that both foam and are filled into bottles are best suited for filling in an overflow filling machine. The reason for this is that the overflow filling machine is a “closed loop” system that captures the product and the foam during the filling process. Generally speaking, the overflow filling machine is ideally suited for filling products that are foamy into containers with fairly small openings like quart and gallon containers. This filling technology is also the least expensive and easiest to operate for the user.

It should be noted that pressurization of the product and containers takes place on this type of filling machine. Some products may be unsuitable for this pressurization particularly in the case where a faulty setup could cause pressurized hazardous chemicals to spray personnel or cause premature aging of the machine due to constant wetted exposure. This case, a time gravity filler would be better suited even though there is a small compromise in the best foam handling and a little slower throughput.

As noted above, these NFCI chemicals are also filled into bulk containers e.g. five gallon pails and even larger totes that have large openings and a large airspace to fill; these containers are usually not suitable for filling on overflow filling machines because in the first case, the container cannot practically be sealed to close the loop of the filling fluid path, and in the second case, the amount of foam creation due to the size of airspace would overwhelm the system’s ability to control it. In both these circumstances, a time gravity system or net weigh system is better suited to the task. The choice here between the time gravity and net weigh filling machines would be determined on how the product is sold i.e. by volume or net weight.

It is fairly obvious as to what the criteria would be for choosing the Net Weigh Filling Machine and so we will not pursue it further here.

The Time Gravity Filling Machine is often used for filling free flowing, non-foaming, non-flammable chemicals because of lower relative capital cost and flexibility of container size and geometry. These machines can be used to efficiently fill both containers with smaller openings as well as large bulk containers with large openings. However, if the product is foamy, the time gravity filling machine may not be as efficient as the overflow filling machine for filling containers, especially with small openings. Although time gravity filling machines can be configured with subsurface and “bottom up fill” filling nozzles to control foam in smaller containers, this configuration does reduce throughput. On large containers filling either foamy or non foamy chemical products, the time gravity filling machine with subsurface filling capability is a very practical machine to use since the overall throughput requirement on bulk containers is usually low. Time Gravity Filling Machines are also preferred where it is not practical to pressurize or recirculate dangerous chemical products like corrosives or explosives. For more information about this, see the section of hazardous location and corrosive filling machines.

Time Gravity Filling Machines are less expensive to purchase than other types of filling machines but they have higher operational and maintenance costs. Because each filling station has an independently programmed filling valve and fluid path, there is a lot of initial setup time required to configure the machine for each application. Moreover, because of mechanical wear of the valves and hysterisis of fluid paths on this machine, the setup parameters are always being adjusted to keep the machine filling accurately. It must also be noted that any chemicals whose bulk density changes with ambient temperature or batch variations will not perform accurately over time on this type of filling machine. There is also more demand on the operators to keep this machine tuned properly and therefore more risk of costly and inaccurate fills over the period of ownership.

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The servo filling machine will fill almost any product of a vast viscosity range , foaming or non foaming, particulate or non particulate. It is also possible to fill multiple products simultaneously on the same machine. It will handle almost any fill size and also almost any container size…..and it will changeover and cleanup almost instantaneously. This flexibility and versatility comes a price. Because each fill head has its own dedicated motor, pump and nozzle combination, the capital cost is significantly higher than conventional filling machines. But for a long term investment, a contract packager will be assured that there is hardly a project they could not consider because they did not have a filling machine capable of doing the job.

Some expensive food products or commodity products with low margins that are filled in bulk are filled by weight either because of economics or because that is the way the product is normally sold. A fine commodity example of this is edible oil that when filled in bulk, it is important for the producer to not give away any extra product. In the case of edible oil, the containers are usually imprecise vessels and moreover, the product volume varies with ambient temperature. These factors make volumetric filling of edible oil impractical in bulk; the solution is a Net Weigh Filling Machine. Another example is high value extracts and flavorings that are normally sold by weight for obvious reasons. The Net Weigh Filling Machine is very accurate but are typically slower speed and often reserved for the realm of bulk filling. The delivery method of the products are also either by gravity or by pump which means that these products typically are free flowing in nature with few if any particulates. The Net Weigh Filling Machine is well understood and valuable in circumstances described above but they are not as prevalent the bottle filling marketplace (other than bulk filling) owing to their higher capital cost and fairly low output.